Pneumatic concatenation of under thread with needle thread to form lock stitches



May 23, 1967 s. J. KETTERER 3,320,911

PNEUMATIC CONCATENATION OF UNDER THREAD WITH NEEDLE THREAD TO FORM LOCK STITCHES Filed July 9, 1964 7 Sheets-Sheet 1 39 ley Keffer May 23, 1967 s. J. KETTERER 3,320,911

PNEUMATIC CONCATENATION OF UNDER THREAD WITH NEEDLE THREAD TO FORM LOCK STITCHES 7 Sheets-Sheet 2 Filed July 9, 1964 INVENTOR. Stanley J. Kefferer A 1 TORNE May 23. 1967 s. J. KETTERER 3,320,911 PNEUMATIC CONCATENATION OF UNDER THREAD WITH NEEDLE THREAD TO FORM LOCK STITCHES Filed July 9, 1964 '7 Sheets-Sheet 3 Fig. ll.

INVENTOR.

Stanley Ketferer 7 ;,,,4. .CLW 4120mm May 23, 1967 5. J. KETTERER 3,320,911

PNEUMATIC CONCATENATION OF UNDER THREAD.WITH NEEDLE THREAD TO FORM LOCK STITCHES 7 Sheets-Sheet 4 Filed July 9, 1964 A E p I INVENTOR. Stanley J. Keflerer BY WZTTORNEY May 23, 1967 5. J. KETTERER 3,320,911

PNEUMATIC CONCATENATION OF UNDER THREAD WITH NEEDLE THREAD TO FORM LOCK STITCHES 7 Sheets-Sheet 5 Filed July 9, 1964 I NVENTOR.

-z2|SianIey J. Ketterer Fig.9.

May 23, 1967 s. J. KETTERER 3,320,911

PNEUMATIC CQNCATENATION OF UNDER THREAD WITH NEEDLE THREAD TO FORM LOCK STITCHES Filed July 9, 1964 7 Sheets-Sheet 6 INVENTOR.

May 23. 1967 s. J. KETTERER 3,320,911

PNEUMATIC CONCATENATION OF UNDER THREAD WITH NEEDLE THREAD TO FORM LOCK STITCHES Filed July 9, 1964 7 Sheets-Sheet 7 INVENTOR.

Stanley J. Kefferer BY W ATTORNEY United States Patent PNEUMATIC CONCATENATION 0F UNDER TImEAD WITH NEEDLE THREAD TO FORM LOCK STITCI-IES Stanley J. Ketterer, Morris Plains, N.J., assignor to The Singer Company, New York, N.Y., a corporation of New Jersey Filed July 9, 1964, Ser. No. 381,358 25 Claims. (Cl. 112-154) This invention relates to the art of sewing; to a new and advantageous method of concatenating threads to form stitches; and to novel and effective mechanisms for producing stitches in accordance with the new method.

The formation of stitches by the concatenation of threads involves the formation of loops in the thread and the passage through said formed loops of other loops or lengths of thread. Heretofore, both the formation of thread loops and the passage of other threads therethrough has been accomplished and accompanied by tangible mechanical instrumentalities, i.e., a needle, a looper, a shuttle, a hook, etc. These known thread manipulating elements require great precision in manufacture, involve extreme intricacy of surface characteristics, and must be moved in carefully regulated and timed relation.

It is an object of this invention to provide in the art of concatenating threads to form stitches, the novel method of forming thread loops by the action of a stream of air and of utilizing a stream of air to pass thread loops or lengths of thread through other thread loops to form stitches.

The terms blow, blowing, blown will be used herein broadly to denote the influence of an air stream for thread concatenation whether the air stream results from the application of a positive pressure or from a vacuum or suction.

The practice of the novel methods of this invention provide not only for the elimination of thread manipulating instrumentalities heretofore essential in the concatenation of threads to form stitches, but also provide other advantages. For instance, a loop of thread through which a loop or length of thread is blown need be only a fraction of the size of a thread loop adapted to accommodate a mechanical instrumentality accompanying the thread loop or thread length to be passed therethrough. This reduction in thread loop size is particularly marked in the formation of lock stitches, where needle thread loop expansion is required to encompass a shuttle or hook bobbin thread case, the method of this invention requires expansion of needle thread loop only slightly larger than the diameter of a thread to be blown therethrough.

It is also an object of this invention to provide novel devices, combinations, and arrangements of parts in a sewing machine for concatenating threads to form stitches by blowing a length of thread through a thread loop.

Another object of this invention is to provide a sewing machine utilizing a stream of air to blow a locking thread through successive needle thread loops to form lock stitches in which the thread concatenating air stream is also utilized for replenishing the supply of locking thread as well as for disposing of thread ends severed from the seam.

With the above and other objects and advantages in view as will hereinafter appear, this invention is illustrated in the accompanying drawings of a preferred embodiment in which:

FIG. 1 represents a head end elevational view of a sewing machine equipped with devices essential to operation in accordance with this invention and illustrating in dot and dashed line a thread in one possible position under 3,320,91 l Patented May 23, 1967 ice the influence of the thread concatenating instrumentalities,

FIG. 2 is an enlarged head end elevational view of the stitch forming devices of the sewing machine illustrated in FIG. 1 and illustrating in dot and dashed line a thread in another possible position under the influence of the thread concatenating instrumentalities,

FIG. 3 represents a vertical cross sectional view of a sewing machine having this invention applied thereto,

FIG. 4 is an enlarged bottom plan view of the cloth plate of the sewing machine of FIG. 3 illustrating the thread concatenating instrumentalities and the thread cutting device,

FIG. 5 is an enlarged cross sectional view taken substantially along line 5-5 of FIG. 4 including work fabrics and threads in place at the conclusion of a sewing operation with the thread cutting device positioned in readiness to cut the thread,

FIG. 6 is an enlarged rear elevational view of the sewing machine of FIG. 3,

FIG. 7 is a horizontal cross sectional view taken substantially along line 7--7 of FIG. 3 illustrating the thread nipper in the opened position occupied when the machine is stopped and with the work supporting bed illustrated in top plan,

FIG. 7A is an enlarged horizontal cross sectional view of the thread nipper in the closed position,

FIG. 7B is a horizontal cross sectional view of the thread nipper in the position occupied during sewing,

FIG. 8 is an enlarged cross sectional view taken substantially along line 88 of FIG. 3 showing a portion of the sewing machine pattern cam with the camming arrangement for the thread nipper and the thread cutting device,

FIG. 9 is a front elevational view of the sewing machine of FIG. 3,

FIG. 10 is a cross sectional view through the sewing machine bracket arm and air valve taken substantially along line Iii-10 of FIG. 3 with the valve illustrated in a position so as to direct air from right to left past the needle path as illustrated in FIG. 1,

FIG. 11 is a cross sectional view through the air valve similar to FIG. 10 but with the valve illustrated in a position to direct air from left to right past the needle path as illustrated in FIG. 2,

FIG. 12 is a cross sectional view taken transversely of the valve substantially along line 1212 of FIG. 10,

FIG. 13 is a cross sectional view taken transversely of the valve substantially along line 1313 of FIG. 10,

FIG. 14 is a cross sectional view taken transversely of the valve substantially along line 1414 of FIG. 10,

FIG. 15 is a cross sectional view taken transversely of the valve substantially along line 15-15 of FIG. 11,

FIG. 16 is a cross sectional view taken transversely of the valve substantially along line 16-16 of FIG. 11,

FIG. 17 is an enlarged vertical cross sectional view of the needle and thread concatenating means taken substantially along line 17-17 of FIG. 9 and showing a first needle thread loop being introduced to the thread concatenating means,

FIG. 18 is an enlarged top plan view of the thread concatenating means and the thread in the position of parts of FIG. 17,

FIG. 19 is a front elevational view of the thread concatenating means and the thread in the position of parts of FIG. 17,

FIG. 20 is a front elevational view of the thread concatenating means showing the free extremity of the first needle thread loop carried into the air conduit in readiness to sew,

FIG. 21 is an enlarged vertical cross sectional view of the needle and thread concatening means taken substantially along line 1717 of FIG. 9 and showing a needle thread loop being introduced to the thread concatenating means on the formation of the first stitch,

FIG. 22 is a front elevational view of the thread concatenating means and the thread in the position of parts of FIG. 21,

FIG. 23 is a front elevational view of the thread concatenating means similar to FIG. 22 but with the thread illustrated during the passage of a loop of locking thread through the needle thread loop,

FIG. 24 is a front elevational view of the thread concatenating means similar to FIG. 22 but with the thread illustrated with the locking thread passed completely through the needle thread loop,

FIG. 25 is a front elevational view of the thread concatenating means similar to FIG. 22 but with the thread illustrated with the needle thread loop drawn up into the work fabric completing the first stitch,

FIG. 26 is a front elevational view of the thread concatenating means showing the needle thread loop being introduced to the thread concatenating means on the formation of the second stitch,

FIG. 27 is a front elevational view of the thread concatenating means similar to FIG. 26 but with the locking thread passed completely through the needle thread loop, and

FIG. 28 is a front elevational view of the thread concatenating means similar to FIG. 26 but with the thread illustrated with the needle thread loop drawn up into the work fabric completing the second stitch.

Referring to the accompanying drawings, FIG. 1 illustrates in a general way an arrangement of parts and devices on a sewing machine for producing stitches in accordance with the method of this invention. In FIG. 1 the sewing machine frame is indicated at 31 and includes a work supporting throat plate 3'2 and provision for supporting a thread carrying needle 33 for endwise reciprocation through the throat plate. Carried beneath the throat plate on the sewing machine frame is a thread positioning member 34 which serves to engage and manipulate loops of thread from the needle relatively to a pair of opposed thread accommodating conduits 35 and 36 which are secured in opposed and aligned relation beneath the throat plate and adjacent to the path of needle reciprocation. The thread accommodating conduits 35 and 36 terminate in opposed spaced orifices 37, 38 beneath the throat plate, and the conduits are connected by tubes 39 and 40 respectively to a valve means 41 on the sewing machine frame. The valve means 41 receives a supply of compressed air from a supply line 42 and serves, as will be described in detail hereinbelow, to direct a flow of air alternately through the tubes 39, 40 in opposite directions through the conduit orifices 37, 38 in timed relation 'with the needle reciprocating mechanism of the sewing machine. The compressed air, whether it is directed into the tube 39 and out of the tube 40 or into the tube 40 and out of the tube 39, is expelled by the valve 41 into an exhaust line 43 which is directed to a vented receptacle 44 which is preferably carried by a support table 45 for the sewing machine.

As illustrated in FIG. 1 in dot and dashed lines, a thread T which extends from the needle 33 through the throat plate 32 is entered in the space between the conduit orifices and extends through the orifice 37 and into the conduit 35 and is sustained in the conduit 35 and tube 40 connected thereto by the stream of air directed therein in the direction indicated by the arrow in FIG. 1 by the valve means 41. Although the thread T illustrated in FIG.1 emanates from the needle 33, it will be appreciated that any thread length introduced to the conduit 35 will be similarly sustained in the conduit 35 and tube 40 by the air stream. Referring to FIG. 2, the thread T is illustrated in the position which it will occupy upon reversal of the flow of air in the conduits 35, 36 by operation of the valve means. Such reversal of the direction of air flow in the conduits will carry the thread T from the 4 conduit 35 and tube 40 through the space between the orifices 37, 38, and into the conduit 36 and tube 39 to be sustained in this position by a flow of air through the conduits 35, 36 in a direction indicated by the arrow in FIG. 2.

With the above described general organization of sewing instrumentalities in mind, the method of stitch formation of this invention may be explained with the particular reference to FIGS. 20 to 25 of the drawings. In these figures a work fabric situated above the sewing machine throat plate 32 is indicated at W and a length of thread 50 extends from the work W through the throat plate 32 through the orifice 37 and into the conduit 35 at the start of a stitch forming cycle as illustrated in FIG. 20. FIGS. 21 and 22 illustrate the disposition of a loop of thread 51 which is projected through the work W by the needle 33 and carried by the thread positioning member 34 into a position substantially straddling the conduits 35, 36. The thread positioning member 34 carries one limb of the thread loop 51 into the space between the conduit orifices 37, 38 and as illustrated in FIGS. 21 and 22 positions that one limb of the thread loop tightly against a bridge portion 64) joining the conduits 35, 36. It will be appreciated that the bridge portion 60 is not essential to the stitch forming process and the thread loop 51 may be carried by the thread position member into a position completely straddling the conduits 35, 36. With the thread loop 51 so positioned, FIG. 23 illustrates the disposition of the length of thread 50 as a stream of air is directed through the conduit 35 into and through the conduit 36. The length of thread 50 will be formed into a loop by the stream of air and passed as a loop through the space 'between the orifices 37, 38 into the conduit 36, in so doing passing through the thread loop 51. Continued flow of air from the conduit 35 to and through the conduit 36 will carry the extremity of the length of thread 50 into the conduit 36, thus blowing the length of thread 50 completely through the thread loop 51, as illustrated in FIG. 24. FIG. 25 illustrates the position of the thread after the thread loop 51 has been drawn into the work W and a lock stitch has been formed. As indicated by the arrow in FIG. 25, continued passage of a stream of air from the conduit 35 to the conduit 36 during such setting of the stitch serves to apply tension on the thread length 50 for control of the characteristics of the stitch set into the work.

With the threads disposed at the setting of a stitch as illustrated in FIG. 25, the thread length 50 may be shifted back into the conduit 35 by reversing the flow of air in the conduits 35 and 36 as indicated in FIGS. 1 and 2 so that a plurality of successive stitches indentical to that illustrated in FIG. 25 may be formed in succesion. The thread length 50 may, however, be permitted to remain in the conduit 36 during the formation of the next needle thread loop 52 as illustrated in FIG. 26. After the needle thread loop 52 has been positioned by the thread positioning member 34 so as to straddle the conduits 35, 36 as illustrated in FIG. 26, the thread length 50 may be passed through the needle thread loop 52 by the action of a stream of air directed from the conduit 36 into and through the conduit 35 as illustrated in FIG. 27. When the thread loop 53 has been drawn into the work W to form a stitch as illustrated in FIG. 28, the thread length 50 will have been concatenated therewith in a direction oposite to the concatenation with the previous needle thread loop 51. It will be appreciated, therefore, that using the method of this invention it is possible to blow one loop of thread through another in the formation of stitches, it is possible to blow a length of thread completely through a loop of thread in the formation of stitches and specifically in the formation of lock stitches. it is possible to produce successively identical stitches as in the federal stitch type 301 as well as lock stitches in "which the direction of looking thread concatenation through the needle thread loop is changed on alternate stitches.

Although the foregoing method description concerns particularly various forms of lock stitches, it will be appreciated that this method of thread concatenation utilizing streams of thread concatenating air may be used as well as in the formation of chain stitches.

FIGS. 17 to 20 in the drawings illustrate the novel method provided by the present invention for replenishing under or locking thread for subsequent use in the formation of lock stitches. FIGS. 17, 18, and 19 illustrate a cross sectional, top plan, and elevational view respectively of the disposition of an initial loop of the thread 50 from the needle 33 after the needle has been raised and the initial thread loop has been engaged by the thread positioning member 34. The initial thread loop will be positioned as during sewing, above described, with one limb directed into the space between the conduit orifices 37, 38 against the bridge portion 60 and the other limb against the exterior of the conduit 36. By directing a stream of air in either direction between the conduits 35, 36 when the thread positioning member 34 is shifted into retracted position as illustrated in dotted lines in FIG. 17, the limb of the thread 50 in the space between the conduit orifices 37 and 38 will be drawn into one of the conduits 35, 36 as illustrated in FIG. 20. This extremity of thread in the conduits 35, 36 then becomes locking thread for use in subsequent lock stitch formation.

The force of the air stream through the conduits 35, 36 may be used to draw a longer length of thread extremity into the conduits from the needle, or the needle may be caused to penetrate repeatedly through'the same point in the work in which case successive bights in the thread 50 will be presented by the needle to the thread positioning member 34 and the conduits 35 and 36, but sewing cannot begin because one limb of each such successive bight will extend to the conduits 35 and 36. Controlled relaxation of the tension applied to the thread which is directed to the needle 33 while the needle penetrates the same point in the work during locking thread replenishment may be used to provide for the replenishment'of an accurately metered quantity of locking thread in the conduits 35 and 36. p

FIGS. 3 to 9 illustrate in detail a sewing machine construction particularly adapted to operate in accordance with the above described methods both of locking thread replenishment and of lock stitch sewing utilizing streams of compressed air to manipulate and concatenate the thread.

' The sewing 'machine illustrated in FIGS. 3 to 9 is in general details of construction substantially similar to that described in detail in the United States patent of Graham'eta'l. No. 2,938,477, May 3 1, 1960, to which reference may be had. These general details comprise a machine frame including a work supporting bed 70 carried on a subbase 71 and a standard 72 rising from the subbase and formed with a bracketarm 73 overhanging the work supporting bed. A main shaft'74 journaled in the bracket arm isoperatively connected to impart endwise reciprocatory movement to a needle'bar 75 journaled in the'bracket arm to which needle bar the needle 33 is secured. The main shaft 'is also operatively connected to oscillate a needle thread take-up lever 76 in the bracket arm.

A pattern cam 77 journaled beneath the subbase and having a gear 78 fast thereon is driven from a worm 79 on the main shaft 74 by means of a vertical shaft 80' in the standard having a ,worm wheel 81 in mesh with the worm 79 and a pinion 82 in mesh with the gear 78. The pattern cam 77 serves three functions in substantially identical fashion to that disclosed in the referenced Gra ham et al. patent, No. 2,938,477; namely, the cam serves by way of two follower rollers 83, 84 which track cam grooves in the upper surface of the cam to impart shifting motion to a work clamp 85 disposed between the work supporting bed and the bracket arm. The work clamp 85 includes a lower jaw 86 overlying the work supporting bed and an upper jaw 87 which may be elevated to release work fabrics by means of an operative influenced clamp lifting lever 88 carried in the standard. The pattern cam 77 serves by way of a pair of cam lugs 89, 90 as illustrated in FIG. 8, to trip a cam follower arm 91 for the purpose of effecting stopping of the main shaft 74 by the influence of a stop motion device 92. The stop motion device is shifted manually into a position to impart motion to the main shaft by a lever -93 carried in the standard. The pattern cam 77 also serves by way of a cam follower 94 which tracks a cam groove 95 in the pattern cam to shift a thread trimmer actuating bar 96 slidable lengthwise in the bed into a position of readiness to sever the sewing threads at a time which coincides with the stopping of the main shaft by the stop motion device. The cam groove 95, moveover, is formed with a slot 97 opening to the periphery of the pattern cam 77 to free the follower 94 from constraint in the stopped position of the machine at which time the thread trimmer actuating bar 96 is thus freed for manual shift in response to motion imparted by a lever 98 and link 99 which connect the thread trimmer actuating bar 96 with the clamp lifting lever 88. It is the operation of the clamp lever 88, therefore, which influences thread trimming operation of the thread trimmer actuating bar 96. The thread trimmer as illustrated in FIGS. 4 and 5 is similar to that disclosed in the above referenced United States Patent No. 2,938,477 to the extent that the trimmer is operated by a rack 100 secured to the trimmer actuating bar 96 and meshing with a gear segment 101 carried on a stud 102 depending beneath the throat plate as illustrated in FIG. 4. The trimmer, however, differs slightly from that disclosed in the referenced patent in that secured for turning movement with the stud 102 is a thread separating finger 103 formed at one side with a radially extending sharpened thread cutting edge 104. The thread separting finger 103 is adaptedto swing across beneath a needle aperture 105 in the throat plate and through a needle thread loop carrying the limb of needle thread loop which leads to the needle on the side opposite the cutting edge and the work limb of the needle thread loop together with the under or locking thread on that side which is formed with the cutting edge 104. A ledger blade 106 cooperating with the cutting edge 104 is carried on a lever 107 pivoted at 108 beneath the bed and formed with an aperture 109 embracing a cam 110 on the stud 102 which serves to retract the leger blade while the trimmer is inetfectiveand to shift the ledger blade into a position closely adjacent to the needle aperture 105 when the thread trimmer is operated.

The pattern cam 77 in the present invention performs one function which has no counterpart in the referenced Graham et'al. United States Patent No. 2,938,477 namely, that of operating a combination auxiliary thread tensioning and thread nippingdevice indicated generally as in FIGS. 3 and 7 and 7A and 7B.

The thread tensioning and nipping device 120 comprises a bracket 121 secured to the sewing machine bracket arm 73 by a'screw 122 and including a bearing boss 123 adapted endwise slidably to accommodate a slide rod 124. The bearing boss 123 is also formed with -a threaded counterbore 125 adapted to accommodate a sleeve 126 also slidably accommodating the slide rod 124. The sleeve 126 is locked relatively to the bearing boss by a lock nut 127. Straddling the bearing boss 123 and slidably embracing thesleeve 126 and slide rod 124 are the bifurcated arms 128, 129 of a sheet metal member 130 which extends between the sewing'machine bracket arin 73 and the bracket 121 and is formed with a finger 131 overlying the bracket 121 as illustrated in FIG. 7 to prevent turning movement of the member 130. A light coil spring 132 interposed between the arm 129 and a collar 133 fast on the sleeve 126 biases the member 130 toward the bearing boss 123. The slide rod 124 has fast at its free extremity a collar 134 which constrains on the slide rod a pair of opposed thread tension disks 35, 36 between the collar 134 and the arm 128 of the member 130.

The slide rod 124 is pivot-ally connected to a control rod 140 which extends through the standard 72 and constrains between a collar 141 fast on the control rod 140 and a bearing plate 142 on the standard a coil spring 143 which biases the control rod in the direction of the tensioning and nipping device 120. Rearw-ardly beyond the standard a sleeve 144 slidable on the control rod is formed with a depending flange 145 which extends perpendicular to the control rod and rests upon a support plate 146 formed on a bearing boss 147 secured to the standard. A light coil spring 148 constrained between the sleeve 144 and a collar 149 on the control rod biases the sleeve and the flange 145 depending therefrom toward the standard and against a pair of out-turned fingers 150, 151 extending from diametrically opposite sides of a cam follower shaft 152 journaled in the bearing boss 147. At the lower extremity of the cam follower shaft 152 is secured a cam follower finger 153 biased by a spring 154 on the cam follower shaft against the outer periphery 155 of the pattern cam 66. Secured on the outer periphery 155 of the pattern cam 77 as by screws 156 is a cam plate 157 to which separate cam lugs 158 are secured in spaced relation by screws 159. The cam plate 157 and the cam lugs 158 are disposed for engagement with the follower finger 153 and together with the outer periphery 155 of the pattern cam provide three different positions for the cam follower and consequently three different positions for the slide rod 124 in the tensioning and nipping device 120.

As illustrated in FIGS. 7 and 8, the cam follower finger 153 when it engages the cam plate 157 at the beginning of a sewing cycle positions the out-turned fingers 150 and 151 both in engagement with the flange 145 thus positioning the control rod 140 in an extreme position toward the tensioning and nipping device 120 and shifting the pair of thread tension disks 135, 136 in spaced relationship with the bifurcated arm 129 constrained against the lock nut 127 preventing the spring 132 from biasing the tension disks into opposition. In this position all frictional resistance to passage of the thread is removed.

When the cam follower 153 engages one of the cam lugs 158, the out-turned finger 151 will be turned by the shaft 152 to shift the control rod 140 to the right as viewed in FIG. 7 drawing the slide rod 124 into an extreme position toward the bearing boss 123 as illustrated in FIG. 7A. In this position, the thread tension disks 135, 136 will be drawn tightly together nipping the thread tightly therebetween. During the thread replenishing operation at the beginning of each stitching cycle, therefore, the thread tensioning device will operate between positions of completely released and completely closed thread nip ping relation. Preferably the cam lugs 158 are positioned to be effective to nip the thread during the take-up stroke of the take-up lever 76 so that the thread will be drawn from a supply spool and not from one of the conduits 35, 36 when the needle rises. The number of cam lugs 158, therefore, can be made to coincide with the number of needle penetrations during which the thread replenishing operation is desired to continue.

During sewing the cam finger 153 will drop onto the pattern cam periphery 155 and the out-turned finger 150 will be turned by the shaft 152 to shift the control rod 3 follower finger 153 tracks the pattern cam periphery 155. The arms 128 and 129 of the member will be in spaced relationship from the bearing boss 123 and the lock nut 127 so that the thread tensioning disks will be biased together by the action of the light coil spring 132 to provide a light auxiliary thread tension which nicely controls the needle thread during sewing.

Referring to FIGS. 3, 4, and 9 as well as to FIGS. 17 to 28, the air conduits 35 and 36 are preferably formed as an integral tube having a surface depression 171 within which depression the opposed orifices 37, 38 are formed by the provision of a vertical slot cut partially through the tube leaving a rear wall of the tube to define the bridge portion 60. Bushing members 173 secured at opposite sides of the work supporting bed 70 as by fastening screws 174 accommodate the integral tube defining air conduits 35 and 36 which is fixed in the bushing members 173 by set screws 175 with the opposed orifices disposed laterally to one side of the needle aperture 105 as illustrated in FIG. 9 and preferably disposed rearwardly of the needle aperture, i.e., toward the standard 72 as illustrated in FIG. 4.

The machine of this invention does not include a mechanical thread concatenating member beneath the work support as is common in lock stitch sewing machines heretofore. For the successful operation of the machine of this invention, it is necessary only that each loop of thread presented by the needle straddle the conduit orifices 37, 38 so that the air stream may pass the locking thread therethrough. While it is possible to attain such thread loop disposition using the needle alone by virtue of the fact that thread limbs from the needle will be separated by the diameter of the needle so that one limb may be detained at one side of the orifices while the other limb may be passed therebetween to straddle the orifices, a thread positioning member 34 has been found to be of considerable value in positively controlling the disposition of the needle thread loops in the desired manner.

The thread positioning member 34 comprises an upstanding flat finger 179 formed with a shallow forked extremity 180 and secured by screws 181 to a collar 182 journaled beneath the bed on a stud shaft 183. The collar 182 is formed with a gear segment 184 meshing with a gear 185 carried on a bed shaft 186 journaled in bear ings 187 beneath the bed. A rock arm 188 fast on the bed shaft is pivotally connected to a bell crank 189 journaled beneath the bed which bell crank is in turn pivotally connected to an eccentric strap 190 extending upwardly through the standard and embracing an eccentric 191 fast on the main drive shaft 74.

Oscillation of the bed shaft thus provides a nodding motion of the thread positioning member 34 in a vertical plane beneath the needle aperture 105. Preferably, as illustrated in FIGS. 9 and 22, the thread positioning member 34 is disposed such that one side 192 thereof passes in close proximity to the needle 33 while the other side 193 moves in a plane intersecting the space between the orifices 37 and 38 of the opposed air conduits 35 and 36. The thread positioning member 34 is timed to move toward the air conduits after the needle has completed penetration and the fork 180 serves to seize the needle thread loop with one limb thereof extending along each side 192, 193. Continued movement of the thread positioning member carries the thread limb on the one side 193 into the space between the orifices 37 and 38 and the thread limb on the other side 192 against the surface depression 171 of the tube so that the thread loop will thereby straddle the air conduits.

Referring to FIGS. 3, and 9 to 16, the specific structural details of the valve means 41 will now be described whereby a stream of air is directed alternately to the conduits 35 and 36 and always exhausted through the exhaust line 43.

As illustrated in FIGS. 3 and 10, a drive gear 200 fast on the main drive shaft 74 meshes with a driven gear 201 having twice the pitch diameter and made fast on a valve shaft 202 journaled in a bushing 203 which is threadedly mounted atop the bracket arm 73. The bushing 203 is formed with a flanged upper extremity 204 defining the bottom wall of the fixed casing of the valve. The body of the valve casing is provided by a block 205 closed by a top wall 206 secured by bolts 207 which threadedly engage the bottom wall 204.

The block 205 providing the body of the valve casing is formed with a vertical cylindrical bore 208 accommodating a valve stem indicated generally at 209 which is secured to or may be made integral with the valve shaft 202. The valve stem is formed between its extremities with a solid cylindrical section 210 which divides the cylindrical bore 208 into an upper chamber 211 and a lower chamber 212. The valve stem above the solid cylindrical section 210 is slabbed along a diameter to define a portion 213 of a semi-circular cross section as illustrated in FIGS. 12 and 16 so that the upper chamber 211 will be similarly semi-circular. An additional vertical depression 213 may be formed in the portion 213 to insure free flow of air from the chamber 211 into the exhaust tube 43. Beneath the solid cylindrical section 210 the valve stem is formed with an annular recess 214 and, in addition, is slabbed at the opposite side from the portion 213, along a chord substantially parallel to the diameter along which the cross section 213 is slabbed and thus provides a lower slabbed portion 215. Beneath the annular recess 214 the lower chamber 212 is therefore slightly less than semi-circular in configuration as illustrated in FIGS. 14 and 15.

The block 205 is formed with a tapped hole 216 which intersects the vertical cylindrical bore 208 opposite the annular recess 214 forming a portion of the lower chamber 212 as illustrated in FIG. 13. The tapped hole 216 accommodates a threaded connector 217 which joins a shut-off valve 218 and the supply line 42 to the valve means 41.

The block 205 is formed with two vertical bores 220 and 221 each substantially parallel to and at diametrically opposite sides of the bore 208. Slots 222 and 223 respectively, are formed in the block 205 at diametrically opposite sides of the bore 208 and join the bore 208 beneath the solid cylindrical section 210 of the valve stem with the respective bores 220 and 221. As the valve shaft rotates, the lower chamber 212 will communicate alternatively with the bores 220 and 221 and because the valve stem beneath the solid cylindrical section 210 is slabbed along a chord, the bores 220 and 221 will never both communicate with the chamber 212 simultaneously. A hose connector 224 threaded into the block 205 com municates with the bore 220 and accommodates the tube leading to the air conduit 35 while a hose connector 225 threaded into the block 205 communicates with the bore 221 and accommodates the tube 39 leading to the air conduit 336.

Slots 226 and 227 respectively, are formed in the block 205 at diametrically opposite sides of the bore 208 and vertically above the slots 222 and 223. The slots 226 and 227 join the bore 208 above the solid cylindrical section 210 of the valve stem with the vertical bores 220 and 221. As the valve shaft rotates, the upper chamber 211 will communicate alternately with the bores 220 and 221.

FIG. 10 illustrates the position of the valve stem 209 while air is directed from the supply line 42 and threaded connector 217 to the tube 39 and from the tube 40 into the exhaust line 43. FIG. 13 illustrates the manner in which the annular recess 214 continuously places the supply tube 42 in communication with the lower chamber 212 of the valve. FIG. 14 clearly illustrates that in the position of the valve shown in FIG. 10, the lower chamber 212 opens onto the slot 223 to direct air into the vertical bore 221, while FIG. 12 illustrates that the upper section 213 of the valve closes the slot 227 thus directing the compressed air into the threaded connector 225 and to the tube 39. FIG. 12 also illustrates that in the position of the valve shown in FIG. 10, the upper chamber 211 of the valve opens onto the slot 226 and connects the tube 40 and threaded connector 224 with the exhaust line 43. FIG. 11 illustrates the position of the valve stem rotated approximately 180 from the position illustrated in FIG. 10 and FIGS. 15 and 16 which are similar to FIGS. 12 and 14 respectively, indicate the manner in which the flow of air is reversed, i.e., directed into the tube 40 and from the tube 39 into the exhaust tube 43. Since the valve stem 202 is preferably driven at one-half the speed of the main shaft 174. This reversal of air flow will occur between each needle reciprocation, thus providing for the formation of stitches illustrated in FIG. 28. It will be appreciated that the relative speed of the valve stem and the main shaft might be selected, for instance, at a 1 to 1 ratio thus to provide for two reversals of the air flow during each needle penetration. Such an arrangement would be used when conventional federal type 301 lock stitches are to be formed in which the locking thread must be passed through each needle thread loop in the same direction.

Operation FIGS. 3, 7, 8, and 9 illustrate the position of the sewing machine parts while the sewing machine is at rest between cycles of operation. The thread nipping device 120 will be held in completely opened position as illustrated in FIG. 7 when the needle makes the first work penetration upon starting of the sewing machine by depression of the starting lever 93, since the cam follower finger 153 will ride upon the cam plate 157. The initial needle thread loop will, therefore, be positioned by the thread positioning member 34 as illustrated in FIGS. 17, 18, and 19 and as the valve 41 turns into the position illustrated in FIG. 11, air will be directed from the orifice 38 to the orifice 37 to carry the thread extremity into the tube 40. As the needle rises after the initial work penetration, the cam finger 153 controlling the thread nipping device 120 rides upon the first of the cam lugs 158 shifting the nipping device 120 into completely closed position as illustrated in FIG. 7A. As the needle thread take-up lever 76 rises to draw up its loop of thread, therefore, the closed nipper 120 will prevent the thread extremity from being withdrawn from the tube 40 by the take-up lever and instead the take-up Will draw thread from the supply spool.

If a greater quantity of under or locking thread is required than can be thus drawn into the tube 40 on one needle penetration, the pattern cam 77 can be formed so as to detain the work clamp unmoved during a plurality of successive needle penetrations. The needle will thus penetrate the same point in the work fabric successively and on each of such penetrations the follower finger 153 will drop onto the cam plate 157 to completely release the thread nipping device. The thread extremity will be shifted back and forth between the tubes 39 and 40 as the valve 41 is rotated and on each penetration that additional increment drawn from the supply by the take-up of thread will be drawn by the flow of air into the tubes. The embodiment illustrated in the drawings illustrates three cam lugs 158 for locking the thread nipping position after three successive needle penetrations during which replenishment thread is delivered to the air tubes.

Following replenishment of the locking thread in the air tubes, the follower finger 153 drops onto the outer periphery 155 of the pattern cam 77 thus positioning the thread nipping device into the position illustrated in FIG. 7B in which a light tension is imposed on the needle thread and the pattern cam 77 begins to shift the work clamp 85. On succeeding needle penetrations, stitches will be formed as illustrated in FIGS. 21 to 28.

When the sewing machine is stopped by the stop motion device 92 at the completion of sewing, the thread trimmer cam follower 94 will be arranged opposite the open slot 97 in the cam groove 95 of the pattern cam 77 and the thread trimmer will occupy the position illustrated in FIGS. 4 and 5. When the work clamp 85 is opened by depression of the lever 88, the thread trimmer will thus be operated by way of the bar 96 to sever the work limb of the needle thread loop caught by the separating finger 103 and to sever the locking thread from the work. Since the locking thread will be arranged in the tube 40 and subject to the air stream directed therethrough, when this thread is severed, the severed extremity will be carried through the tube 40, valve 41 and exhaust tube 43 into the receptacle 44 and the sewing machine will be in readiness for the insertion of a fresh work piece.

What is claimed is:

1. A a sewing machine comprising an endwise reciprocatory needle adapted to form a loop in a firs-t thread limb through a work piece, pneumatic means for passing a second thread limb through said loop formed by said needle through said work piece, and actuating means for operating said reciprocatory needle and said pneumatic means in timed relation.

2. A sewing machine comprising an endwise reciprocatory needle adapted to form a loop in a first thread limb through a work piece, a conduit adapted to accommodate a second thread limb and having an orifice adjacent to the path of reciprocation of said needle, and means for passing a stream of air through said conduit to blow said second thread limb through said loop in said first thread limb formed by said needle through the work piece.

3. A sewing machine comprising an endwise reciprocatory needle adapted to form a loop in a first thread limb through a work piece, actuating mechanism operatively connected to said needle, a conduit adapted to accommodate a second thread limb and having an orifice adjacent to the path of reciprocation of said needle, and valve means operated in timed relation with said actuating mechanism for passing a stream of air through said conduit to blow said second thread limb through a loop in said first thread formed by said needle through the work piece.

4. A sewing machine comprising an endwise reciprocatory needle adapted to form a loop in a first thread limb through a work piece, actuating mechanism operatively connected to said needle, a pair of conduits each adapted to accommodate a second thread limb, said conduits each formed with an orifice, said orifices arranged opposite one another in spaced relationship adjacent to the path of reciprocation of said needle, and valve means operated in timed relation with said actuating mechanism for directing a stream of air between said opposed orifices from one to the other of said conduits to pass said second thread limb through a loop in said first thread limb formed by said needle through the work piece.

5. A sewing machine comprising an endwise reciprocatory needle adapted to form a loop in a first thread limb through a work piece, actuating mechanism operatively connected to said needle, a pair of conduits each adapted to accommodate a second thread limb, said conduits each formed with an orifice, said orifices arranged opposite one another in spaced relationship adjacent to the path of reciprocation of said needle, and valve means operated in timed relation with said actuating mechanism for directing a stream of air between said opposed orifices alternately from one to the other of said conduits to pass said second thread limb through successive loops in said first thread formed by said needle through the work piece.

6. A sewing machine comprising an endwise reciprocatory needle adapted to form a loop in a first thread limb through a work piece, actuating mechanism operatively connected to said needle, a pair of conduits each adapted to accommodate a second thread limb, said conduits each formed with an orifice, said orifices arranged opposite one another in spaced relationship adjacent to the path of reciprocation of said needle, and valve means operated in timed relation with said actuating mechanism for directing a stream of air between said opposed orifices alternately from one to the other of said conduits on alternate needle reciprocations to pass said second thread limb alternately in opposite directions through successive loops in said first thread formed by said needle through the work piece.

'7. A machine for concatenating two limbs of thread to form stitches in a work piece and including a work piece support, a needle adapted to carry one of said limbs of thread, actuating mechanism operatively connected to said needle for imparting endwise work penetration movement to said needle to carry said one limb of thread through the work piece on said work support, a conduit formed with an orifice disposed adjacent to the position of said needle upon work penetration of said needle, means for positioning a second of said limbs of thread through said orifice and into said conduit, means operated in timed relation with the endwise work penetrating movement of said needle for positioning said thread limb carried through said work piece by said needle in a loop substantially straddling said conduit orifice, and valve means operated in timed relation with said actuating mechanism for directing a stream of air from said conduit outwardly through said orifice to blow said second limb of thread through said positioned loop of said first limb of thread.

8. A sewing machine comprising an endwise reciprocatory needle adapted to form a loop in a first thread limb through a work piece, actuating mechanism operatively connected to said needle, a conduit adapted to accommodate a second thread limb and having an orifice adjacent to the path of reciprocation of said needle, a needle thread loop spreading member, means operated in timed relation with said actuating mechanism for operating said loop spreading member to engage and carry said needle thread loop into a position substantially straddling said orifice, and valve means operated in timed relation with said actuating mechanism for passing a stream of air through said conduit to blow said second thread limb through said spread needle thread loop.

9. A sewing machine comprising an endwise reciprocatory needle adapted to form a loop in a first thread limb through a work piece, actuating mechanism operatively connected to said needle, a-pair of conduits each adapted to accommodate a second thread limb, said conduits each formed with an orifice, said orifices arranged opposite one another in spaced relationship adjacent to the path of reciprocation of said needle, a needle thread loop spreading member, means operated in timed relation with said actuating mechanism for operating said loop spreading member to engage and carry said needle thread loop into a position substantially encompassing the space between said orifices, and valve means operated in timed relation with said actuating mechanism for directing a stream of air between said opposed orifices from one to the other of said conduits to pass said second thread limb through said spread needle thread loop.

10. A sewing machine comprising an endwise reciprocatory needle adapted to form a loop in a first thread limb through a work piece, actuating mechanism operatively connected to said needle, a pair of conduits each adapted to accommodate a second thread limb, said conduits each formed with an orifice, said orifices arranged opposite one another in spaced relationship adjacent to the path of reciprocation of said needle, a needle thread p spreading member, means operated in timed relation with said actuating mechanism for operating said loop spreading member to engage and carry each successive needle thread loop into a position substantially encompassing the space between said orifices, and valve means operated in timed relation with said actuating mechanism for directing flow of a stream of air between said opposed orifices alternately from one to the other of said conduits to pass said second thread limb through successive loops in said first thread formed by said needle through the work piece.

11. A sewing machine comprising an endwise reciprocatory needle adapted to form a loop in a first thread limb through a work piece, actuating mechanism operatively connected to said needle, a pair of conduits each adapted to accommodate a second thread limb, said conduits each formed with an orifice, said orifices arranged opposite one another in spaced relationship adjacent to the path of reciprocation of said needle, a needle thread loop spreading member, means operated in timed relation with said actuating mechanism for operating said loop spreading member to engage and carry each successive needle thread loop into a position substantially encompassing the space between said orifices, and valve means operated in timed relation with said actuating mechanism for directing flow of a stream of air between said opposed orifices alternately from one to the other of said conduits on alternate needle reciprocations to pass said second thread limb alternately in opposite directions through successive spread needle thread loops.

12. A sewing machine comprising an endwise reciprocatory needle adapted to form a loop in a first thread limb through a Work piece, actuating mechanism operatively connected to said needle, a take-up member engaging said first thread limb, means operated in timed relation with said actuating mechanism for rendering said take-up member effective subsequent to formation of a loop in said first thread limb by said needle, a conduit adapted to accommodate a second thread limb and having an orifice adjacent to the path of reciprocation of said needle, means for passing a stream of air through said conduit orifice to blow said second thread limb from said conduit through said loop in said first thread limb formed by said needle through the work piece, and means for maintaining passage of said stream of air through said orifice while said take-up member is rendered effective.

13. A sewing machine comprising an endwise reciprocatory needle adapted to form a loop in a first thread limb through a work piece, actuating mechanism operatively connected to said needle, a pair of conduits each adapted to accommodate a second thread limb, said conduits each formed with an orifice, said orifices arranged opposite one another in spaced relationship adjacent to the path of reciprocation of said needle, a needle thread loop spreading member, means operated in timed relation with said actuating mechanism for operating said loop spreading member to engage and carry each successive needle thread loop into a position substantially encompassing the space between said orifices, a take-up member engaging said first thread limb, means operated in timed relation with said actuating mechanism for rendering said take-up member effective subsequent to the spreading of each successive needle thread loop by said loop spreader, and valve means operated in timed relation with said actuating mechanism for directing flow of a stream of air between said opposed orifices alternately from one to the other of said conduits on alternate needle reciprocations to pass said second thread limb alternately in opposite directions through successive spread needle thread loops, said valve means including provision for maintaining said flow of a stream of air on each successive needle reciprocation While said take-up member is rendered effective.

14. A sewing machine comprising an endwise reciprocatory needle adapted to form a loop through the work piece in a first thread limb of a seam being stitched in said work piece actuating mechanism operatively connected to said needle, a pair of conduits each adapted to accommodate a second thread limb of a seam being stitched in said work fabric, said conduits each formed with an orifice, said orifices arranged opposing one another in spaced relationship adjacent to the path of reciprocation of said needle, means for severing said second thread limb between said seam being stitched in said work piece and said conduit orifices, valve means operated in timed relation with said actuating mechanism for directing flow of a stream of air between said opposed orifices from a first of said pair of conduits into a second of said pair of conduits to convey said second thread limb through said loop in said first thread limb formed by said needle through the work piece, a thread collecting receptacle, and valve means interconnecting said second of said pair of conduits with said receptacle.

15. A sewing machine comprising an eye pointed thread carrying needle, actuating mechanism for imparting a series of successive endwise reciprocations to said needle to project successive loops through a work piece of a thread, the free extremity of which is initially threaded through the eye of the needle, a thread accommodating conduit having an orifice adjacent to the path of reciprocation of said needle, pneumatic means effective on the initial needle reciprocation of said series of needle reciprocations to draw the free extremity of thread projected through the Work fabric by said needle through said orifice and into said conduit, pneumatic means for passing said free extremity of said thread from said conduit orifice through a subsequent loop in said thread projected by said needle through said work piece to form a lock stitch, and means operated in timed relation with said actuating mechanism for operating said pneumatic means.

16. A sewing machine for forming lock stitches in a Work piece comprising a frame having a work support formed with a needle aperture, a thread carrying needle supported above said work support and adapted to carry a needle thread, actuating mechanism in said frame for reciprocating said needle endwise through said work piece and said needle aperture, a tube supported beneath said work support transversely of the path of reciprocation of said needle, said tube formed between its ends with a transverse slot adjacent to the path of reciprocation of said needle defining opposed spaced orifices through which a locking thread is adapted to be accommodated into said tube, a shiftable needle thread loop spreading member carried beneath said work support, means operated by said actuating mechanism for shifting said loop spreading member in timed relation with said needle reciprocation to carry one limb of each needle thread loop through said tube slot, a valve means carried by said frame, a source of air under pressure connected to said valve means, conduits connect ing each end of said tube with said valve means, an exhaust duct connected to said valve means, and means driven by said actuating mechanism for operating said valve means to direct a flow of compressed air from said source alternately into said conduits while alternately connecting the other of said conduits to said exhaust duct in timed relation with the operation of said needle and loop spreading member to pass said locking thread through each successive needle thread loop.

17. A sewing machine as set forth in claim 16 in which said valve drive means is arranged to effect one change of the direction of flow of compressed air through said tube during each needle reciprocation.

18. A sewing machine as set forth in claim 16 in which said valve drive means is arranged to efiect two changes in the direction of flow of compressed air through said tube during each needle reciprocation.

19. A look stitch sewing machine having a work penetrating thread carrying needle, a needle thread take-up member, actuating mechanism for reciprocating said needle alternately to penetrate and withdraw from a work piece and for rendering said take-up member effective during each withdraw-a1 stroke of said needle, and a thread concatenating means including a conduit having an orifice adjacent to the path of reciprocation of said needle, means for directing a fiow of air through said conduit to manipulate a locking thread therein, and a loop spreading member operated by said actuating mechanism in timed relation with said needle reciprocation for spreading loops of needle thread across said conduit orifice, means for replenishing a metered quantity of locking thread in said conduit from a thread extremity carried by said needle comprising a thread controlling device operative on said needle thread at a point on said needle thread between said needle and said take-up member, and operative mechanism for said thread controlling device driven by said actuating mechanism and effective during locking thread replenishment for rendering said thread controlling device inefiective to retard passage of needle thread during the work penetrating stroke of said needle and effective completely to block passage of needle thread between said needle and said take-up member during the withdrawal stroke of said needle.

20. A lock stitch sewing machine as set forth in claim 19 in which said thread controlling device includes opposed thread frictioning elements between which the needle thread is directed, and in which said operating mechanism therefor includes a push rod influencing the spacing of said thread frictioning elements, and in which means are provided for positioning said push rods during sewing so as to influence a slight frictional resistance to passage of the needle thread relatively to the thread controlling device.

21. The method of concatenating threads relatively to a work piece in the formation of a stitch which comprises projecting a loop in a first length of thread through the work piece, and utilizing a stream of air impinging directly upon a second length of thread to pass a loop in said second length of thread through said projected loop in said first length of thread.

22. The method of forming a lock stitch in a work piece comprising passing a loop in a first length of thread through the work piece, blowing one extremity of a second length of thread completely through said loop in said first length of thread passed through said work piece, and drawing said loop in said first length of thread into said work piece after the free extremity of said second length of thread has been blown therethrough.

23. The method of forming a lock stitch by manipulation of two lengths of thread relatively to a work piece comprising projecting a loop in a first length of thread through said work piece, blowing a second length of thread through said projected loop of said first length of thread by a stream of moving air directed through said projected loop, drawing said projected loop of said first length of thread into said work piece, and maintaining said second length of thread in a stream of moving air during said drawing of said projected loop into said work piece.

24. The method of producing a lock stitch scam in a work piece comprising, passing successive loops in a first length of thread through the work piece at intervals in the direction of the seam, blowing a free extremity of a second length of thread in seriatim through each of said successive loops in said first length of thread, and drawing each of said loops in said first length of thread into said work piece after the free extremity of said second length of thread has been blown therethrough.

25. The method of producing a seam of lock stitches by manipulation of two lengths of thread relatively to a work piece comprising carrying said two lengths of thread relatively to said work piece in the direction of the seam, projecting successive loops of a first of said length of thread through said work piece, sustaining each of said successive projected loops in similar orientation relatively to the work piece to said direction of the seam, blowing one extremity of the second of said lengths of thread completely through each of said projected loops of said first length of thread in seriatim by a stream of moving air directed through each of said projected loops, reversing the direction of said stream of moving air through alternate ones of said projected loops, and drawing each projected loop of said first length of thread into said work piece after the extremity of said second length of thread has been blown therethrough.

JORDAN FRANKLIN, Primary Examiner.

RICHARD J. SCANLAN, JR., Examiner. 

1. A SEWING MACHINE COMPRISING AN EDWISE RECIPROCATORY NEEDLE ADAPTED TO FORM A LOOP IN A FIRST THREAD LIMB THROUGH A WORK PIECE, PNEUMTIC MEANS FOR PASSING A SECOND THREAD LIMB THROUGH SAID LOOP FORMED BY SAID NEEDLE THROUGH SAID WORK PIECE, AND ACTUATING MEANS FOR OPERATING SAID RECIPROCATORY NEEDLE AND SAID PNEUMATIC MEANS IN TIMED RELATION. 